Drools release pipeline: Antora documentation handling in release pipeline is not working

Release pipeline is raising a failure with the new Antora call that has been added to the deploy pipeline in case of a release: https://github.com/kiegroup/drools/blame/8.22.x/.ci/jenkins/Jenkinsfile.deploy#L104-L106

2 reasons to that:

• `drools-docs` module is never defined into the main pom.xml, thus never built and the `.ci/jenkins/update_antora_yml.sh` script is failing
  => it should be added to the `full` profile
• the drools-docs module is failing to build due to `src/modules/ROOT/pages/.index.adoc`. File is not present into the repository.

Note that for the 8.22.x release, this step is ignored:

• https://github.com/kiegroup/drools/pull/4389 (will be backported to `main`)
• https://github.com/kiegroup/drools/pull/4392 (ignore the step on 8.22.x)